Lung ultrasound useful in diagnosis of community-acquired pneumonia

NEW YORK (Reuters Health) – Lung ultrasound (LUS) is useful for diagnosing and following up community-acquired pneumonia (CAP), according to a new report.

“LUS offers several different applications, especially if chest X-ray is not available (in point-of-care ultrasonography, in emergency units, in a general practitioner practice) or not applicable,” said Dr. Angela Reissig, whose findings were published online June 14 in Chest.

“In cases with sonographic evidence of pneumonia, the diagnosis can be established and the therapy can start immediately,” Dr. Reissig, from Friedrich-Schiller-University Jena in Germany, told Reuters Health by email.

She and her colleagues sought to determine the accuracy of LUS in diagnosing CAP compared with 2-plane chest x-ray and, when x-ray was negative or equivocal, with low-dose CT.

LUS correctly diagnosed CAP in 211 of 226 patients with confirmed CAP, for a sensitivity of 93.4%. Sonographic signs of pneumonia were lacking in 127 of 130 patients without CAP, for a specificity of 97.7%.

Chest x-ray alone was slightly less sensitive (199/215, 92.6%) and slightly more specific (122/122, 100%) than LUS for diagnosing CAP.

Twenty-six cases of LUS-detected CAP were missed or equivocal by x-ray, whereas 14 cases of x-ray-detected CAP were missed by LUS.

Sonography also proved useful for documenting disease remission, and results of follow-up LUS were concordant with follow-up x-rays in 85 (75.6%) patients.

“About 8% of pneumonic lesions are not detectable by LUS,” the researchers write. “Therefore, an inconspicuous LUS does not exclude pneumonia.”

“We have shown that it is possible to diagnose and follow-up CAP by LUS with a very good sensitivity and specificity (at least comparable with chest X-ray in two planes),” Dr. Reissig concluded.